Rotary switch



. March 20, 1962 Filed Jan. 25, 1958 H. F. MASON 3,026,586

ROTARY SWITCH 3 Sheets-Sheet 1 wmao F Mass/u,

Iwvsurm? March 1962 H. F. MASON 3,026,386

ROTARY SWITCH Filed Jan. 23, 1958 3 Sheets-Sheet 2 .HZwnep M1950 H. F. MASON ROTARY SWITCH March 20, 1962 3 Sheets-Sheet 3 I 16:

Filed Jan. '23, 1958 HEM/HEB Masa/u,

United States Patent 3,026,386 ROTARY SW [1 CH Howard F. Mason, Los Angeles, Calif., assignor to Mason Electric Corporation, Los Angeles, Calif., a corporation of California Filed Jan. 23, 1958, Ser. No. 710,796 28 Claims. (Cl. 200-68) The present invention relates in general to electric switches and, more particularly, to a switch which op erates with a snap action to provide a fast make and break to minimize arcing, which operates in a positive manner in the sense that the movable contact snaps from one operative position to another without any possibility of hesitating etween such positions, which operates in this manner irrespective of how the switch is manipulated manually by the operator, which provides a positive feel so that the operator can readily tell that the switch has advanced from one operative position to another, and so forth.

More particularly, the invention relates to a switch which is similar to and achieves the results attainable with the switches disclosed and claimed in my copending application Serial No. 325,401, filed December 11, 1952, now Patent Number 2,831,082, granted April 15, 1958, of which the present application is a continuation-in-part, a general object of the invention being to provide a switch which is an improvement on those disclosed in said copending application.

Considering the switch of the present invention in a general way, it includes a contact path having two or more spaced recesses therein which define operative positions of a movable contact, the latter being a roller contact adapted to roll along the contact path. More particularly, the invention contemplates a switch wherein the contact path is arcuate and concave, defining either part of a circle, or a complete circle, and wherein stationary contacts are located at at least certain of the recesses in the contact path, such recesses being formed in the respective stationary contacts. Thus, the roller contact engages stationary contacts in one or more of its operative positions wherein it is received in one of the recesses, the contact path being formed of electrically insulating material between the stationary contacts.

The switch of the invention further includes an actuating means for moving the roller contact along the contact path, and into and out of each of the recesses therein, which includes a pivotable or rotatable actuator, hereinafter referred to as a rotary actuator, and a resilient lostmotion connection between such actuator and the roller contact which'permits the roller contact to remain in the recess in which it is disposed until the actuator has been rotated through an angle sufiicient that the energy stored in the resilient lost-motion connection causes the rotatable contact to jump from the recess in which it is disposed into the next recess with a snap action. This resilient lost-motion connection between the rotary actuator and the roller contact includes kicking means limiting the range of relative angular movement between the rotary actuator and the roller contact for positively displacing or kicking the roller contact out of the recess in which it is disposed, whereupon the energy stored in the resilient lost-motion connection carries the roller contact all the way into the next recess on the contact path irrespective of how the rotary actuator may be manipulated manually, or otherwise, after the roller contact leaves the recess in which it is initially disposed.

The switch of the invention still further includes a rotor which carries the roller contact and which is rotatable about the center of curvature of the concave contact path by the rotary actuator through a rotation transmitting means which interconnects the rotor and the roice tary actuator and which provides the resilient lost-motion connection hereinbefore discussed, the rotary actuator also being rotatable about the center of curvature of the contact path. The roller contact is resiliently biased into engagement with the contact path and, in the preferred embodiment of the invention, this is accomplished by resilient means acting between the rotor and a contact carrier which is movable relative to the rotor in a direction toward and away from the center of curvature of the contact path, and thus toward and away from the contact path itself.

With the foregoing general background, a primary object of the present invention is to provide a switch wherein the resilient lost-motion connection includes spring means carried by the rotor adjacent the outer periphery thereof and having arms which extend radially inwardly toward the center of curvature of the contact path into engagement with the rotary actuator, such spring means comprising at least one torsion spring having a coil carried by the rotor adjacent the outer periphery thereof and providing the arms mentioned.

Another object is to provide the rotary actuator and the rotor with stops respectively engageable with the arms of each torsion spring in such a manner that the arms are moved relative to each other in a direction to stress the coil of the torsion spring in response to rotation of the rotary actuator relative to the rotor with the roller contact disposed in a recess in the contact path. With this construction, energy is stored in the coil of each torsion spring to cause the roller contact to jump from the recess in wh ch it is disposed into the next recess upon movement of the roller contact out of the recess in which it is initially disposed.

Another object of the invention is to provide on the rotary actuator a kicking means which operates to rotate the rotor after limited rotation of the rotary actuator relative thereto so as to kick the roller contact out of the recess in which it is disposed so that the energy stored in the coil of each torsion spring may be utilized to carry the roller contact into the next recess. In this connection, another object is to provide a kicking means on the rotary actuator comprising a kicker engageable with that arm of each torsion spring which is engageable with a stop on the rotor so that such kicker forces the spring arm in question against the stop on the rotor to force the rotor to rotate after limited rotation of the rotary actuator relative thereto, thereby forcing the roller contact out of the recess in which it is disposed.

Another object of the invention is to provide spring means acting between the roller contact carrier and the rotor for biasing the roller contact into engagement with the contact path, such spring means also comprising at least one torsion spring having an arm engaging the contact carrier and having an arm which engages the rotor.

Another object is to provide a resilient means for biasing the roller contact into engagement with the contact path which includes spring means comprising a torsion spring having an arm in engagement with the contact carrier and another arm in engagement with the rotary actuator so that rotation of rotary actuator relative to the rotor results in the application of an increased spring force to the roller contact to maintain it in the recess in which it is disposed until it is kicked out of such recess at the end of the range of limited movement of the rotary actuator relative to the rotor. With this construction, the roller contact is positively held in the recess in which it is disposed until the kicking means comes into operation, thereby insuring a positive, controlled jump to the next recess.

Another object is to provide a switch wherein the torsion spring or springs for biasing the roller contact into engagement with the contact path also include coils carried-by the rotor adjacent the outer'periphery thereof. The foregoing use of torsion springs having radially inwardly extending arms to bias the roller contact into engagement with the contact path and to store the energy required to cause the roller contact to jump from one recess fo theh'extwhn it is forced out of the first recess by thekicking means, results in a very simple and compact structure and permits a substantial reduction in switch'si'ze for a given capacity,'which are important features "of the invention.

Another object is to provide a switch of the foregoing nature wherein the stationary contacts are 'oifset laterally from the portion of the contact path which is formed of the electrical insulating material. In other words, the contact path is formed with circumferentially spaced and circumferen'tialiy aligned segments of electricalinsulating material and-the stationary contacts are offset laterally from such'seg'rnents and disposed opposite the spaces therebetween. With this construction, the portions of 'the roller contact which engage the stationary contacts do not engage the insulated segments, the insulated segments being engaged by'diilerent portions of the roller contact. Thus, the roller contact does not track metal from the stationary contacts onto the insulated segments, thereby avoiding the eventual current leakage between stationary-contacts that such metal tracking would produce, which is an important feature of the invention.

Still another object of the invention is to provide means for minimizing arcing between the roller contact and the stationary contacts which comprises making the contact; carrier a shell capable of substantially completely enclosing the roller-contact on both sides and both ends, the contact carrier being open only on the side thereof which faces the contact path. The shell forming the contact carrier is substantially in engagement with the contact path when the roller contact is disposed in each recess, the clearance between the contact .path and the contact carrier being not more than about 0.015 inch. With this construction, any are which may exist must pass through a very narrow gap, which gap is reduced to a very small dimension when the roller cou tact is in one'of the recesses in the contact path. Thus, arcing is minimized as the roller contact'is moving from "one recess to the other and extinguishing of the arc is insured when the roller contact drops into the next recess due to the substantial engagement of the contact carrier with the contact path.

Another object with respect to minimizing arcing 'is to provide on the rotor arc barriers on opposite sides of p the rollercontact, such are barriers being-of electrical insulating material and being substantially in sliding engagement with the contact path'to provide a highly constricted arc chute through which any are must travel,

whereby even moreelfective arc quenching results, which is an important feature.

The foregoing objects, advantages, features and results of the present invention, together with various other ob- :jects, advantages, features and results thereof which will be evident to those skilled in the switch art in the light of this disclosure, may be attained with the exemplary embodiments of the invention described in detail hereinafter and illustrated in the accompanying drawings, in

which:

FIGS. 1, 2, 3 and 4 are views respectively illustrating successive positions of a semidiagrammaticrepresentation of an electric switch of the invention;

FIG. 5 is a longitudinal sectional view of an electric switch which embodies the invention;

FIG. 6 is a transverse sectional view taken along the arrowed line 66 of FIG. 5;

FIG. 7 is an enlarged, fragmentary sectional view taken along the arrowed line 77 of FIG. 5 and illustrating the components-of the switch in one set of relative posit o s;

' FIG. 8 is a view similar to FIG. 7, but illustrating Cir 4 the switch components in another set of relative positions;

FIG. 9 is a sectional view taken along the arrowed line 9-9 of FIG. 7;

FIG. 10 is a sectional view taken along the arrowed line E i-10 of FIG. 8;

FIG. 11 is a fragmentary perspective view of contact biasing and contact jumping means of the invention;

FIG. 12 is a fragmentary developed view of a contact path incorporated in the switch of the invention;

FIG. 13 is a perspective view of a contact carrier of the invention;

FIG. 14 is a perspective view of a. stationary contact of the invention; and

FIG. 15 is a perspective view-of an arc barrier of the invention.

Referring first to FIGS. l'to 4 of the drawings, portrayed therein is a switch 2! which illustrates the invention semidiagrmmatically to show the fundamental principles thereof more clearly. The switch includes a structure 22 which provides a contact path 24. having circumferentially spaced recesses 26 and 28 therein,.the contact path being arcuate and concave and the recesses facing radially inwardly toward the center of curvature 30 of the contact path. At least one of the recesses 26 and 23 is formed in a stationary contact on the'contact path 24, both of the recesses 26 and 28 being formed in stationary contacts 32 and 34, respectively, in the particular constructionillustrated. The structure 22 betweenthe stationary contacts 32 and 34 is-formed of electrical insulating material.

Movable along the contact path 24 and receivable in each of-the recesses 26 and -28 is a roller contact 36 rotatably mounted in a contact carrier 38 by means of an axle 4% The contact carrier 38 is carried by a rotor 42 having therein a radial slot. 44 which receives a shaft 46 at thecenter of curvature 30 of the contact path 24 to permit movement of the roller contact 36 into and out of each of-the-recesses 26 and 28. .The contact carrier. and the rotor 42-are biased away from the center of curvature 30 of the contact path 24 by a compression spring 48 acting between the contact carrier 38 and theshaft 46,

whereby thisspring biases the roller contact into engage ment with the contact path.

it will be understood that while the contact carrier 38 is shown as fixedly mounted on the rotor 42 and the rotor is shown as radially movable toward and away from the contact path 24, the rotor 42 may. be radially-immovable and the contact carrier 38 may be. mounted on the rotor for radial movement relative. thereto toward and away from the center of curvature 30 of the contact path, the spring 48 still acting on the contact carrier 38 under such circumstancesto bias the roller. contact into engagement with the contact path. Such a'structure is incorporated in the actual embodiment of the invention illustrated in FIGS. 5 to 15- of the drawings and described in detail hereinafter.

The switch 20includes a rotary actuator 50 which is rotatable about the center of curvature 30 of the contact path 24, there being a rotation transmitting means 52 which provides a resilient lost-motion connection between the rotor and the rotary actuator for transmitting rotation of the rotary actuator about the center of curvature 1 39 to the rotor after limited rotation of the rotary actuator relative to the rotor. More specifically, the rotation transmitting means 52 comprises two compression springs 54 and 56-each'seated at one end againstthe rotor 42 and at its other-end against the rotary actuator 50. Kickers 58 and 60 on the rotary actuator 50 are engageable with the rotor 42'tolimit rotation of the rotary actuator relative to the rotor to apredetermined range and to displace or kick the roller contact 36 out of the recess 26 or 28 in which it is disposed in a positive manner.

Considering the operation-of the invention'with reference to the semidiagrammatic representation thereof.

provided by the switch 20, 'it' will be assumed that a state of equilibrium exists with the roller contact 36 in the recess 26. Under these conditions, the various components of the switch are in the positions shown in FIG. 1 of the drawings.- In other words, the spring 48 maintains the roller contact 36 in the recess 26, and the springs 54 and 56 position the rotary actuator 50 at the center of the range of limited relative movement between the rotary actuator and the rotor 42.

Assuming that it is desired to move the roller contact 36 from the recess 26 into the recess 28, the rotary actuator 50 is rotated in the counterclockwise direction, as shown in FIG. 2 of the drawings. Until such time as the kicker 58 engages the rotor 42, the spring 48 maintains the roller contact 36 in the recess 26 so that rotation of the rotor 42 is prevented. Consequently, the rotary actuator 50 merely rotates relative to the rotor 42, thereby compressing the spring 54, shown in FIG. 2 of the drawings.

When the limit of the range of rotation of the rotary actuator 50 relative to the rotor 42 is reached, the kicker 58 engages the rotor 42, whereupon further rotation of the rotary actuator results in rotation of the rotor also to force the roller contact 36 out of the recess 26, the roller contact being shown in FIG. 3 of the drawings as having been moved out of the recess 26 into engagement with the edge of such recess which is nearest the recess 28. It will be noted that, in order to move the roller contact 36 out of the recess 26, it is necessary to compress the spring 48, the increasing stress in such spring thus resisting movement of the roller contact out of the recess 26. This provides the device with a positive feel and prevents unintentional displacement of the roller contact 36 out of the recess 26.

As shown in FIG. 4 of the drawings, once the roller contact 36 clears the recess 26, the energy stored in the stressed spring 54 causes very rapid rotation of the rotor 42 relative to the rotary actuator 50 in the counterclockwise direction to cause the roller contact 36 to jump or snap into the next recess 28. The range of relative movement between the rotor 42 and the rotary actuator 50 from the centered or neutral position of the rotor relative to the rotary actuator is such that the energy stored in spring 54 causes the roller contact 36 to jump all the way from the recess 26 to the recess 28, irrespective of any manual manipulation of the rotary actuator 50 which may occur after the roller contact leaves the recess 26. In order to accomplish this, the angular range of relative movement between the rotor 42 and the rotary actuator 50 from the centered or neutral position of the rotor relative to the rotary actuator is at least one-half of the angular spacing of the recesses 26 and 28, and may approach the angular spacing of such recesses.

The energy stored in the spring 54 as the kicker 58 is brought into engagement with the rotor 42 to displace the roller contact 36 out of the recess 26, moves the roller contact from the recess 26 to the recess 28 extreme rapidly. This minimizes arcing as electrical contact is made and/or broken.

It will be understood that the switch 20 operates in a similar manner upon clockwise rotation of the rotary actuator 50, the spring 56 and the kicker 60 operating in the same manner as the spring 54 and the kicker 58.

Turning now to FIGS. 5 to 15 of the drawings, illustrated therein is a switch 70 which represents an actual physical embodiment of the invention, but which has the same general components and operates in the same general manner as the semidiagrammatic representation of the invention depicted by the switch 20.

The switch 70 includes a housing which is shown as comprising an annular shell 72 closed at its ends by discs 74 and 76, these elements being mounted on a base 80 by studs 82 extending through the discs 74 and 76 and threaded into the base 80, and by nuts 84 threaded onto the outer ends of the studs. The base 80 is provided with an externally threaded nipple 86 adapted to extend through a panel, not shown, and to have a nut, not shown, threaded thereon to clamp the base against the panel for the purpose of panel-mounting the switch 70.

Disposed in the annular shell 72 intermediate the discs 74 and 76 is an annulus 88 of electrical insulating material through which the studs 82 extend to hold such annulus in place. The annulus 88 is provided therein with a plurality of circumferentially spaced recesses 90, circumierentially spaced and circumferentially aligned insulating segments 91 between the recesses 90 in the annulus constituting portions of an arcuate, concave contact path 92 for circumierentially spaced roller contacts 94 which will be described in more detail hereinafter. As will be apparent, the center of curvature of the contact path 92 is On the axis of the switch 70.

Respectively located on opposite sides of the annulus 88 in longitudinal alignment with each recess 90 are two stationary contacts 96 adapted to be bridged by each roller contact 94. In other words, the stationary contacts 96 of each pair are ofiset laterally from the insulating segments 91 of the contact path 92 and are located opposite the gap or space between two of such insulating segments which is formed by the corresponding recess 90 in the annulus 88. The stationary contacts 96 are provided with recesses 98 therein intermediate the circumferentially spaced edges thereof, as best shown in FIG. 14 of the drawings, and the recesses 98 in the stationary contacts 96 of each pair are located opposite, i.e., in longitudinal alignment with, one of the recesses 90 in the annulus 88. The recesses 90 in the annulus 88 are deeper than the recesses 98 in the stationary contacts 96 so that, when a roller contact 94 is disposed in the recesses 98 in the stationary contacts 96 of one pair thereof the roller contact is out of engagement with the annulus 88. However, the portions of the stationary contacts 96 adjacent the recesses 98 therein are flush with the portions of the annulus 88 between the recesses 99 in the annulus so that each roller contact 94 rolls smoothly from the insulating segments of the contact path 92 which are formed by the portions of the annulus 88 between the recesses 90 therein onto the portions of the stationary contacts 96 adjacent the recesses 98 therein.

As best shown in FIG. 12 of the drawings, laterally ofisetting the stationary contacts 96 from the insulating segments 91 of the contact path 92 formed by the portions of the annulus 88 between the recesses 90 therein results in positioning the stationary contacts out of circurnferential alignment with the insulating segments of the contact path. Consequently, as each roller contact 94 moves along the contact path 92 over the insulating segments 91 thereof and over the stationary contacts 96, which also form portions of the contact path, the roller contact cannot track metal from the stationary contacts onto the insulating segments of the contact path since the portions of the roller contact which engage the stationary contacts differ from the portions of the roller contact which engage the insulating segments of the contact path. This has the effect of preventing metal deposits on the insulating segments of the contact path 92 which would eventually result in current leakage from one pair of stationary contacts to the next after prolonged usage of the switch 70, offsetting the stationary contacts from the insulating segments of the contact path thus being an important feature of the invention for this reason.

As best shown in FIG. 14 of the drawings, the stationary contacts 96 are L-shaped, one arm of each being provided with the corresponding recess 98 therein and the other arm thereof being secured to the annular shell 72 by a tubular rivet 100, FlG. 5. Threaded into each tubular rivet 100 is a terminal screw 102 by means of which the desired electrical connection to the corresponding stationary contact 96 may be made. In order to insulate the various tubular rivets .100 from each other electrically, the annular shell 72 is formed of electrical posit/e side of such contact carrier.

insulating material. The discs 74 and 76 are also formed of electrical insulating material, and the studs 82 are electrically insulated by insulating sleeves 194 telescoped thereov er between the annulus 83 and the disc 74 and between this annulus and the disc 76, such sleeves thereby also serving to prevent axial movement of the annulus 88.

Considering the remaining components of the switch 70 in a general way, the switch includes a contact carrier 110 for each roller contact 94, a rotor 112 which is rotatable about the axis of the switch and which carries the contact carriers 110, a rotary actuator 114 which is also rotatable about the axis of the switch, rotation transmitting means 116 interconnecting the rotor and the rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of the rotary actuator to the rotor after limited rotation of the rotary actuator relative to the rotor, and spring means 118 for biasing each contact carrier 110 away from the axis of the switch so'asto bias the corresponding roller contact 94 into engagement with the contact path 92 formed by the annulus 88 and the stationary contacts 96. The roller contacts 94 are all identical, as are the contact carriers 110 therefor and the spring means 118 for biasing the roller contacts into engagement with the contact path. Consequently, only one of the roller contacts 94 and the components associated therewith need be considered in detail.

Each contact carrier 11!) consists of a hollow shell having side walls 125 and end walls 122 substantially completely' enclosing the corresponding roller contact 94 to minimize arcing, as hereinafter discussed in detail, the

contact carrier being open only on the side thereof which faces the con-tact path92 to permit engagement of the roller contact with the contact path. Each roller contact 94 is mounted within the corresponding contact carrier 110 on an axle 124 the ends of which project beyond the ends of the roller contact into radial notches or grooves "122 thereof with external radial ribs 128 which are receivable in radial notches 130 in discs 132 forming the ends of the rotor 112, the ribs 128 being radially movable in the notches 130 to permit radial movement of the corresponding roller contact 94 into and out of the recesses '98 in the stationary contacts 96. The discs 132 forming the rotor 112 are journalled on the rotary actuator 114, the latter having a stub shaft 134 journalled in the disc 76 of the switch housing and having another stub shaft 136 journalled in the base 80 of the switch housing and adapted to have a control knob, not shown, fixed thereon. The discs 132 of the rotor 112 are rigidly interconected by circumferentially spaced pins 138 each located adjacent the outer periphery of the rotor 112 between two of the contact carriers 110, and by pins 140 respectively located radially inwardly of the pins 138 and adjacent the inner periphery of the rotor.

Considering the spring means 118 for biasing each roller contact 94 into engagement with the contact path 92, it includes, as best shown in FIGS. 7 to ll, at least two torsion springs 142 and 144. The spring 142 includes a coil encircling the pin 138 on one side of the corresponding contact carrier 1'10, and the spring 144 similarly includes a coil encircling the pin 138 on the op- The springs 142 and 144 respectively include anns 146 and 148 which engage the corresponding contact carrier 110, as clearly shown in FIGS. 7 and 8. The springs 142 and 144 also respectively include arms 158 and 152 which respectively engage two of the pins 140 of the rotor 112, these pins acting as stops :for the arms. 15ilancl 152 ofthe springs springs constantly bias the corresponding contact carrier toward the contact path 92.

Considering now the rotation transmitting means 116,. which, as hereinbefore mentioned, provides a resilient lost-motion connection between the rotor 11?. and the rotary actuator 114, it includes spring means comprising torsion springs 156 and .158 respectively having coils which encircle the pins 138 on opposite sides of one of the contact carriers 118, the coils of the springs 156 and 158 respectively encircling the same pins as the coils of the springs142 and 144 for biasing the Contact carrier in questiontoward the contact path 92. The spring 156 has radially inwardly extending arms 160 and 162 which receive the adjacent pin therebetween and, similarly, the spring 158 is provided with radially inwardly extending arms 164 and 166 which receive therebetween the pin 14% adjacent such spring. The springs 15 6 and 153 are initially so stressed in torsion that the arms thereof are biased into engagement with the corresponding pins 140, which pins serve as stops preventingthese springs, and the springs 142 and 144, from unwinding.

The ,various spring arms 150, 152, 160, 162, 164 and 166 project generally radially inwardly into the rotary actuator 114 and are engageable by stops on such actuator which vwill be described hereinafter. In the particular construction illustrated, the stopsin question are provided by the edges of holesin the rotary actuator 114, but it Will be understood that the stops may be provided by other means, such as longitudinal slots or grooves in the rotary actuator, longitudinal bars forming parts of the rotaryactuator, and the like. Considering the stops mentioned in more detail, the spring arms and 162 are engageable either by a stop 168, or by a stop'17ii. The

arms 152 and l64 are engageable either by a stop 172, or a stop 174. The arm ltiii'is engageable either by a stop 176, or by a stop 178. The arm 166 is engageable by either a stop 180, or a stop 182. The functional interrelations'between the various spring arms and stops will be cousidered in the following paragraphs in describing the operation of the rotation transmitting means 116 between the rotor 112 and the rotary actuator 114.

In considering the operation of the rotation transmitting means 116, it will be assumed that the various parts are in the relative positions shown in FIG. 7 of the drawings and that the rotary actuator 114 is to be rotated in the clockwise direction to advance the corresponding roller contact 94 from the stationary-contact recesses 98 in which it is disposed to the next pair of stationary-contactrecesses in the clockwise direction.

As will be seen in comparing FIGS, 7 and 8 of the drawings, clockwise rotation of the rotary actuator 114 initially produces no rotation of the rotor 112, the springs 142 and 144 acting to maintain the corresponding roller contact 94 in one of the pairs of stationary-contact recesses 98 and thus acting to prevent rotation of the rotor. V However, such initial rotation of the rotary actuator 114 causes the stop 168 to displace the spring arm 150 away fromthe corresponding stop 140 on the rotor, as shown in FIG. 8, thereby increasing the torsional stress in the spring 142 and thus increasing the spring force acting to hold the corresponding roller contact 94 in the pair of stationary-contact recesses 98 in which it is disposed. It will be noted that the torsional stress in the other spring 144 which acts on the corresponding contact carrier 11% is not increased in response to clock- W186 rotation of the rotary actuator 114 relative to the rotor 112. (However, counterclockwise rotation of the rotary actuator 114 relative to the rotor 112 stresses the spring 144, but not the spring 142, to increase the spring force acting on the corresponding roller contact 94 to bias it into engagement with the contact path 92.)

The initial clockwise rotation of the rotary actuator 11% relative to the rotor 112 also causes the stop 168 to 9 move the spring arm 162 away from the corresponding stop pin 140, and causes the stop 180 to move the spring arm 166 away from its corresponding stop pin 140, as shown in FIG. 8, thereby increasing the torsional stresses in the springs 156 and 158. Consequently, energy is stored in these springs.

When the rotary actuator 114 has been rotated relative to the rotor 112 to the extent permitted by the lost motion connection provided by the rotation transmitting means 116, the stop 176 engages the spring arm 160 and the stop 172 engages the spring arms 152 and 164, these spring arms being prevented from moving in the clockwise direction With the rotary actuator 114 by the corresponding stop pins 140. Consequently, the stops 172 and 176 act as kickers to force the rotor 112 to rotate with the rotary actuator 114 upon further rotation of the latter, and thus serve to kick or positively displace the corresponding roller contact 94 out of the stationary-contact recesses 93 in which it is disposed.

At this point, the energy stored in the springs 156 and 153, and in the spring 142, causes the roller contact 94 to jump to the next pair of stationary-contact recesses with a snap action. As hereinbefore discussed in connec tion with the semidiagrammatic representation of the invent-ion illustrated in FIGS. 1 to 4 of the drawings, this jumping of the roller contact 94 from one pair of recesses to the next occurs very rapidly so as to minimize arcing. Also, the energy stored in the springs 1'42, 156 and 158 and the range of relative movement between the rotary actuator 114 and the rotor 112 trom a centered or neutral position of the rotary actuator relative to the rotor are such that the jump of the roller contact to the next pair of recesses occurs irrespective of any manual manipulations which may occur after the roller contact leaves the preceding pair of recesses.

The action of the rotation transmitting means 116 is similar in response to counterclockwise rotation of the rotary actuator 114, except that, as hereinbefore stated, the stop 174 increases the torsional stress in the spring 144 to increase the spring force acting on the corresponding contact carrier 110, there being no increase in the torsional stress in the spring 142 under such conditions. Also, the stops 178 and 174 respectively increase the torsional stresses in the springs 156 and 158, the stops 168 and 180 being inoperative under these circumstances. During counterclockwise rotation, the stops 170 and 182 act as kickers, instead of the stops 176 and 172.

in instances where lesser amounts of stored energy for causing the motor 112 to jump the roller contact 94 into the next pair of recesses may be utilized, one or both of the springs 156 and 158 may be omitted, relying only on the energy stored in that one of the springs 142 and 144 the stress in which is increased in response to clockwise or counterclockwise rotation of the rotary actuator 114 relative to the rotor 112. Thus, varying amounts of stored energy may be utilized, depending upon the rate of roller-contact movement desired.

It will be understood that for each of the roller contacts 94 carried by the rotor 112, there is a set of springs and stops similar to those hereinbefore described and operating in a similar manner so that a detailed description is unnecessary.

While the hereinbefore-discussed rapid roller-contact movement from one pair of stationary-contact recesses 98 to the next minimizes arcing, the present invention provides two additional means for further minimizing arcing. The first of these additional arc-minimizing means includes arc barriers 184 of electrical insulating material between adjacent roller contacts 94, there being one such are barrier between each pair of adjacent roller contacts. The are barriers 184 are disposed between the discs 132 cf the rotor 112 and are suitably secured to such discs. These arc barriers are substantially in sliding engagement with the insulating segments 91 of the contact path 92 formed by the portions of the annulus 88 between the recesses therein, the radial clearance between the arc barriers 184 and the portions of the contact path 92 between the stationary-contact recesses 96 being not more than 0.015 inch. Thus, the arc barriers 184 cooperate with the contact path 92 to provide a highly constricted arc chute through which arcing must occur. Consequently, the arc barriers 184 aid in quenching any arcs Which do form and help in controlling phase-to-phase fiashover. Also, the arc barriers 1S4 act as physical barriers which prevent foreign matter from shorting various components of the switch 70 since they constantly displace any foreign matter which may enter the switch.

Considering the other arc-minimizing means mentioned earlier, each contact carrier 110, as hereinbefore suggested, substantially completely encloses the corresponding roller contact 94. In other words, the side walls 120 and the end walls 122 of the contact carrier cover just as much of the roller contact 94 as possible, the roller contact projecting from the carrier just far enough that the side walls clear the contact path 92 when the roller contact is in one of the pairs of stationarycontact recesses 98. However, the clearance between the side walls and the contact path 92 under such conditions does not exceed 0.015 inch. With this small clearance, even if an arc does form when the roller contact 94 is between two of the pairs of stationary-contact recesses 98, the chute through which the arc must pass is immediately constricted to a thickness of not more than 0.015 inch when the roller contact 94 drops into the next pair of stationary-contact recesses 98. Thus, even if any are which may be formed is not quenched before the roller contact drops into the next pair of stationarycontact recesses 98, the sudden reduction in the size of the arc chute as the roller contact drops into the next pair of D recesses will positively quench any continuing arc.

As a further means of minimizing arcing, the end walls 122 of each contact carrier 110 completely cover the ends of the corresponding rolier contact 94, and the end walls overlap the stationary contacts 96.

Although exemplary embodiments of the invention have been disclosed herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiments without departing from the spirit of the invention as defined by the claims which follow.

What is claimed is:

1. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said re cesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actu ating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including spring means carried by said rotor and spaced radially outwardly from said center of curvature of said contact path and having arms which extend toward said center of curvature of said contact path and which terminate in free ends adjacent said center of curvature of said contact path.

2. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses 3,02e,sse

is formed, said contact path having an angular extent of 360; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lostmotion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including spring means carried by said rotor and spaced radially outwardly from said center of curvature of said contact path and having arms which extend toward said center of curvature of said contact path and which terminate in free ends adjacent said center of curvature of said contact path.

3. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed, said contact path including at least two circumferentially aligned and circumfer'entially spaced segments of electrical insulating material, said stationary contact being ofiset to one side of said aligned segments opposite the space therebetween; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including spring means carried by said rotor and spaced radially outwardly from said center of curvature of said contact path and having arms which extend toward said center of curvature of said contact path and which terminate in free ends adjacent said center of curvature of said contact path.

4. In a switch, the combination of: a contact path including at least two aligned, spaced segments of electrical insulating material and two stationary contacts respectively ofiset to opposite sides of said aligned segments opposite the space therebetween; and a roller contact of a length to bridge the space between said stationary contacts and movable over one of said segments, said stationary contacts and the other of said segments in sequence, whereby one portion of said roller contact engages said segments and other portions thereof engag said stationary contacts to avoid tracking of metal from said stationary contacts onto said segments.

5. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including torsion spring means carried by said rotor and having arms which extend toward said center of curvature of said contact path; and another torsion spring means interconnecting said rotor and said contact carrier for biasing said contact carrier toward said contact path.

6. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; and a rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including a torsion spring having a coil carried by said rotor and having two arms which extend toward said center of curvature of said contact path, said rotary actuator having a stop thereon which is engageable with one of said arms to tend to move said one arm relative to the other of said arms in a direction to stress said coil in response to rotation of said rotary actuator relative to said rotor, said rotor having thereon a stop which is engageable by said other 'arm to prevent movement of said other arm with said one arm in response to rotation of said rotary actuator relative to said rotor so that rotation of said rotary actuator relative to said rotor stresses said coil, said rotary actuator having thereon a kicker which is engageable with said other arm in response to rotation of said rotary actuator relative to said rotor through a predetermined angle to kick said roller contact out of the recess in said contact path in which it is disposed, whereby said stressed coil rotates said rotor relative to said rotary actuator with a snap action to move said roller contact into the next one of said recesses in said contact path.

7 In a switch, the combination of: an arouate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary cont-act in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; a rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including a torsion spring having a coil carried by said rotor and having two arms which extend toward said center of curvature of said contact path, said rotary actuator having a top thereon which is engageable with one of said arms to tend to move said one arm relative to the other of said arms in a direction to stress said coil in response to rotation of said rotary actuator relative to said rotor, said rotor having thereon a stop which is engageable by said other arm to prevent movement of said other arm with said one arm in response to rotation of said rotary actuator relative to said rotor so that rotation of said rotary actuator relative to said rotor stresses said coil, said rotary actuator having thereon a kicker which is engageable with said other arm in response to rotation of said rotary actuator relative to said rotor through a predetermined angle to kick said roller contact out of the recess in said contact path in which it is disposed, whereby said stressed coil rotates said rotor relative to said rotary actuator with a snap action to move said roller contact into the next one of said recesses in said contact path; and another torsion spring interconmeeting said rotor and said contact carrier and biasing said contact carrier toward said contact path, said other torsion spring including a coil carried by said rotor and including arms respectively engaging said rotor and said contact carrier.

8. In a switch, the combination of: an arcuate contact path having -a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lostmotion connection therebtween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor; and means including a torsion spring interconnecting said rotor and said cont-act carrier for biasing said contact carrier toward said contact path, said torsion spring including a coil carried by said rotor and including two arms respectively engaging said rotor and said contact carrier.

9. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lostmotion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including spring means resiliently connecting said rotor to said rotary actuator and carried by said rotor and spaced radially outwardly from said center of curvature of said contact path and including two arms which extend toward said center of curvature of said contact path and which terminate in free ends adjacent said center of curvature of said contact path.

10. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lostmotion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including spring means resiliently connecting said rotor to said rotary actuator and carried by said rotor and including two arms which extend toward said center of curvature of said contact path, said rotation transmitting means including stops respectivelycarried by said rotor and said rotary actuator and respectively engageable with said arms of said spring means so as to stress said spring means in response to rotation of said rotary actuator relative to said rotor, said rotary actuator having thereon a kicker which, after rotation of said rotary actuator relative to said rotor through a predetermined angle, is engageable with that arm of said spring means which is engageable with said stop on said rotor.

11. In a switch, the combination of: an arcuate contact path having a center of curvature and having circurnferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including two spring means respectively carried by said rotor on opposite sides of said contact carrier in circumferentially spaced relation and each having two arms extending to- Ward said center of curvature and connecting said rotor to said rotary actuator.

12. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and panallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor and being movable relative thereto toward and away from said center of curvature of said contact path; and rotation transmitting means interconnecting said rotor motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including two spring means respective- -ly carried by said rotor on opposite sides of said contact carrier in circumferentially spaced relation and each having two arms extending toward said center of curvature and connecting said rotor to said rotary actuator.

13. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses, said contact carrier being a shell which substantially completely encloses said roller contact and which is open only on the side thereof that faces said contact path, said shell being substantially in engagement with said contact path when said roller contact is in one of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor;

, and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lostmotion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotaion of said roary actuator relative to said rotor, said rotation transmitting means including two spring means respectively carried by said rotor on opposite sides of said contact carrier in circum'ferentially spaced relation and each having two arms extending toward said center of curvature and connecting said rotor to said rotary actuator.

14. In a switch, the combination of: a contact path having spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a movable contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses, said contact carrier being a shell which substantially completely encloses said movable contact and which is open only on the side thereof that faces said contact path, said shell being substantially in engagement with said contact path when said movable contactis in one of said recesses; and actuating means for moving said contact carrier adjacent and parallel to said contact path.

15. A switch as defined in claim 14 wherein the clearance between said shell and said contact path does not exceed about 0.015 inch when said movable contact is in one of said recesses.

16. In a switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by .said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor; rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said 16 rotor, said rotation transmitting means including two spring means respectively located on opposite sides of said contact carrier in circumferentially spaced relation and each connecting said rotor to said rotary actuator; and an arc barrier carried by said rotor and circumferentially spaced from said contact carrier in circumferential alignment therewith, said are barrier being substantially in sliding engagement with said contact path and being aligned with said movable and stationary contacts in the direction of said contact path.

17. In a switch, the combination of: a contact path having at least one stationary contact thereon; a movabie contact movable along said contact path and engageable with said stationary contact; an arc barrier spaced from said movable contact in the direction of said contact path and movable with said movable con-tact along said contact path, said arc barrier being substantially in sliding engagement with said contact path and being aligned with said movable and stationary contacts in the direction of said contact path; and means for moving said movable cont-act and said are barrier along said contact path.

18. A switch as defined in claim 17 wherein there is a clearance of not more than about 0.015 inch between said arc barrier and said contact path.

19. In a switch, the combination of: a contact path having spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact rotatably mounted on said contact carrier and engaging and movable along said contact path and receivable in each of said recesses, said contact carrier being a shell having side walls respectively disposed on opposite sides of said roller contact and having end walls respectively disposed at opposite ends of said roller contact, said shell substantially completely enclosing said roller contact and being open only on the side thereof which faces said contact path, said side walls of said shell being substantially in engagement with said contact path when said roller contact is in one of said recesses; andactuating means for moving said contact carrier adjacent and parallel to said contact path.

20. In a switch, the combination of: a contact path having spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact rotatably mounted on said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; an arc banier spaced from said contact carrier in the direction of said contact path and movable with said contact carrier along said contact path, said are barrier being substantially in sliding engagement with said contact path and being aligned with said movable and stationary contacts in the direction of said contact path; and means for moving said contact carrier and said are barrier along said contact path.

21. In a rotary switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a con-tact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of along said carrier path by means including interengageable elements on said contact carrier and said rotor, said rotor including two spaced plates having said contact carrier therebetween, said interengageable elements being on said plates and said contact carrier; and spring means mounted on said rotor and spaced radially outwardly from said center of curvature of said contact path and interconnecting said rotor, said rotary actuator and said contact carrier, and providing a resilient lost-motion connection between said rotor and said rotary actuator, for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor and for biasing said contact carrier toward said contact path so as to bias said roller contact into engagement with said contact path.

22. In a rotary switch, the combination of: an arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including a rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor and being movable relative thereto toward and away from said contact path along a carrier path extending radially from said center of curvature; and spring means mounted on said rotor and spaced radially outwardly from said center of curvature of said contact path and interconnecting said rotor, said rotary actuator and said contact carrier, and providing a resilient lost-motion connection between said rotor and said rotary actuator, for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor and for biasing said contact carrier toward said contact path so as to bias said roller contact into engagement with said contact path, said spring means comprising a plurality of arms mounted on said rotor and engaging said rotor, said rotary actuator and said contact carrier, said spring means also including at least two torsion springs each having a coil mounted on said rotor and each providing two of said arms.

23. A switch according to claim 22 wherein said rotor and said rotary actuator are provided with elements engageable with one of said arms after limited rotation of said rotary actuator relative to said rotor to transmit rotation of said rotary actuator to said rotor.

24. In a switch, the combination of: a contact path including insulating portions of electrical insulating material and conductive portions of electrically conductive material, said insulating portions and said conductive portions being spaced apart in the direction of said contact path, said insulating portions and said conductive portions being misaligned in the direction of said contact path, and said insulating portions and said conductive portions being staggered in the direction of said contact path so that said conductive portions are laterally opposite the spaces between said insulating portions; and a contact movable along said contact path and engageable with said insulating portions and said conductive portions in sequence, difierent parts of said movable contact being engageable with said insulating portions and said conductive portions as said movable contact moves along said contact path so as to avoid tracking of said conductive material onto said insulating material.

25. In a switch, the combination of: an annular arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including an annular rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor and said rotary actuator being disposed Within said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including spring means resiliently connecting said rotor to said rotary actuator and extending generally radially inwardly from within said rotor to within said rotary actuator.

26. In a switch, the combination of: an annular arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including an annular rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor and said rotary actuator being disposed within said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including spring means resiliently connecting said rotor to said rotary actuator and mounted on said rotor outwardly of said rotary actuator and extending generally radially inwardly from within said rotor to within said rotary actuator.

27. In a switch, the combination of an annular arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller contact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including an annular rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor and said rotary actuator being disposed within said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including spring means resiliently connecting said rotor to said rotary actuator and extending generally radially inwardly from within said rotor to within said rotary actuator; said rotation transmitting means including stop means on said rotor and said rotary actuator and engageable with said spring means for stressing said spring means in response to rotation of said rotary actuator relative to said rotor.

28. In a switch, the combination of: an annular arcuate contact path having a center of curvature and having circumferentially spaced recesses therein and having thereon at least one stationary contact in which one of said recesses is formed; a contact carrier movable adjacent and parallel to said contact path; a roller con tact carried by said contact carrier and engaging and movable along said contact path and receivable in each of said recesses; actuating means movable about said center of curvature of said contact path for moving said contact carrier adjacent and parallel to said contact path, said actuating means including an annular rotor and a rotary actuator rotatable relative to said rotor about said center of curvature of said contact path, said contact carrier being carried by said rotor and said rotary actuator being disposed Within said rotor; and rotation transmitting means interconnecting said rotor and said rotary actuator and providing a resilient lost-motion connection therebetween for'transmitting rotation of said rotary actuator to said rotor after limited rotation of said rotary actuator relative to said rotor, said rotation transmitting means including spring means resiliently connecting said rotor to said rotary actuator and extend- References Cited in the file of this patent UNITED STATES PATENTS 1,889,637 Cook Nov. 29, 1932 2,015,399 Grothe Sept. 24, 1935 2,163,919 Siegel June 27, 1939 2,483,115 Wall Sept. 27, 1949 2,554,506 Schwarz May 29, 1951 2,831,082 Mason Apr. 15, 1958 FOREIGN PATENTS 413,976 Great Britain July 26, 1934 571,395 Great Britain Aug. 22, 1945 612,509 Germany Apr. 26, 1935 730,971 France May 24, 1932 473,219 Italy July 18, 1952 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,026,386 March 20, 1962 Howard F. Mason It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 5, line 57, for "extreme" read extremely column 7, lines 56 and 57, for "interconected" read interconnected column 9, line 49, for "motor" read rotor column 13, line 2, for "top" read stop column 15, line 33, for "roary" read rotary Signed and sealed this 10th day of July 1962,

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADD Attesting Officer Commissioner of Patents 

